Garmin Coach MCP

get_hrv

Fetches overnight heart rate variability (HRV) for a date, returning last night's average, weekly average, baseline range, and status to track recovery and autonomic load.

Instructions

Get overnight heart rate variability: last night's average, weekly average, baseline range and status (BALANCED / UNBALANCED / LOW). A recovery and autonomic-load marker.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "get_hrv"
  }
}

Input Schema

Name	Required	Description	Default
`date`	No	Date in YYYY-MM-DD format (defaults to today)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.5.0Oct 1, 2026

TDQS

A4/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden, and it does disclose the returned payload and the status domain (BALANCED / UNBALANCED / LOW), which is genuinely useful behavioral context. It stops short of stating that it is a read-only, single-record lookup or what happens when overnight data is missing.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two tight sentences, front-loaded with the core purpose and followed by supporting context. Every clause earns its place with no redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description appropriately lists the return components, and the single parameter is fully covered by the schema. It is nearly complete, missing only edge-case behavior such as absent overnight data or the default-date fallback (which the schema does mention).

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and the single 'date' parameter is fully documented in the schema (format and default). The description adds no parameter-level meaning beyond that, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb ('Get') and a precisely scoped resource ('overnight heart rate variability'), then enumerates exactly what is returned (last night's average, weekly average, baseline range, status). This clearly separates it from generic siblings like get_heart_rate_data and get_health_metrics.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The phrase 'A recovery and autonomic-load marker' implies the context in which the value matters, but there is no explicit when-to-use/when-not guidance and no named alternative among the many sibling tools. Usage is only implied.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.